Lithotripsy for urinary stones may be carried out intracorporeally using a lithotripsy device including a flexible or rigid ureteroscope configured to fragment each stone and remove the fragments. Laser energy is conventionally used to fragment the stones, although other energies may be used, including those applied by ballistic, ultrasonic, and/or electrohydraulic means. Stone fragmentation is a desirable effect. With many lithotripsy devices, however, the size of each stone fragment cannot be controlled. For example, in response to laser energy, a stone may be broken into a plurality of stone fragments, each having unpredictably different sizes. Fragment size may determine the length of treatment time. For example, larger stones must be removed or further fragmented, else they will most likely grow back into even larger stones.
Accurately measuring stone size is a known problem. Many purported solutions require the surgeon to estimate stone size from an image, such as an X-ray image. These estimations may be inaccurate, especially if the image is of low resolution or visibility. Because of these inaccuracies, the surgeon may remove and/or fragment more stones than otherwise required, or engage in an arduous removal process. Both options are time consuming. For example, time may be lost if the surgeon introduces a retrieval device based on an estimated stone size, then finds the fragment too big, requiring removal of the retrieval device, further fragmentation of the stone, and eventual re-introduction of the retrieval device. Aspects of the methods and systems described herein address these problems and other deficiencies of the prior art.